The extraordinary in the everyday
Reality is stranger than you think.
The surprising odds behind everyday life. Explained visually. Backed by sources.
The birthday paradox
Just 23
people.
A shared birthday is more likely
than you think.
A few things you didn’t see coming.
Trust your gut. Then check it.
Which is more likely?
23 independent, uniformly distributed birthdays across 365 days, or ten independent fair coin tosses?
Assumptions & calculation
Birthday model: 1 − (365 × 364 × … × 343) / 365²³ ≈ 50.73%. Coin model: (½)¹⁰ = 1/1,024 ≈ 0.09766%. These are mathematical models; real birthdays are not uniformly distributed.